This application claims the benefit of Korean Utility Patent Application No. 20-2000-0020978, filed on Jul. 22, 2000, under 35 U.S.C. xc2xa7119, the entirety of which is hereby incorporated by reference.
1. Field of the Invention
The present invention refers to a sack with a detachable hard case. In particular, a hard case is attached to the backside of the sack when heavy articles or fragile articles treated carefully are carried. The sack without the hard case can also be used.
2. Description of Related Art
In general, a sack is a kind of bags that is usually fastened on someone""s shoulder to carry necessary goods conveniently and to protect the goods, especially in climbing, fishing, or traveling. According to usage of the sack, the sack is called by a rucksack, a knapsack, or a packsack, etc. Such a sack is commonly used to carry books and notebooks among students in these days, too. Such a popular usage makes the sack to be produced in various designs and colors to attract a purchaser.
The ordinary sack can be sagged easily when goods are packed in because a material of the ordinary sack is usually a soft synthetic fiber. Such softness gives a non-elegant and uncomfortable to carry the ordinary sack. In more, carrying fragile goods in such a sack can make someone to be nervous to prevent unpredicted external impact.
To improve the above mentioned problems, a hard type sack is presented, wherein a shoulder rack and a back supporter are made of a synthetic resin, for example, a polyester, and a backside case is made of a hard material. The hard type sack fixes rim of the backside case to each side and bottom of the back supporter by jointing bolts.
Usage of the hard type sack has an advantage to keep a shape without sagging when goods are packed in, and to protect the goods from any external impact, because the backside case is made of a hard material.
However, disassembling the backside case from the hard type sack is not easy because the backside case is jointed with the back supporter by bolts and nuts method. In more, bolts are always required to re-assemble the backside case into the hard type sack after disassembling.
To overcome the above described problems, preferred embodiments of the present invention provide a sack having a detachable hard case, wherein the detachable hard case can be attached to the backside of the sack. Therefore, the sack with the detachable hard case is used to carry heave or fragile goods like the hard type sack, and the sack without the detachable hard case is used like an ordinary sack.
Another preferred embodiments of the present invention can apply a protrusion-groove structure to equip the detachable hard case to the sack, and to separate the detachable hard case from the sack conveniently.